Originally Posted by Harkerr
Get the marine deep cycle from Wal
Mart. If you have room go one size larger.
Wal Mart does not sell a true deep cycle 12v battery. It is a dual purpose deep cycle.
You CAN occasionally find 6v true deep cycle batts there...but a pair only is a risk since if one goes bad you have no fallback option. They are great in a 4+ battery boondocking setup. SAMS club usually has them.
Go as large as you can fit in the space is excellent advice.
Group 24....75 amp hours
Group 27... 95 amp hours
Group 31....105 amp hours ... on average.